Just like the sewage system disposes of unwanted waste to keep a city clean, the excretory system works non-stop to remove waste from the body and prevent build up of toxic waste. While kidneys are one of the principal organs of the excretory system, other organs such as the liver, large intestine, skin and lungs work in unison to maintain the right balance of nutrients, water and salts in the body. Read more, published in The Week Smart Life June 2016.